iteye01 阅读(27) 评论(0)

一、ribbon简介

Ribbon is a client side load balancer which gives you a lot of control over the behaviour of HTTP and TCP clients. Feign already uses Ribbon, so if you are using @FeignClient then this section also applies.

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ribbon是一个负载均衡客户端,可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon。

ribbon 已经默认实现了这些配置bean:

IClientConfig ribbonClientConfig: DefaultClientConfigImpl

IRule ribbonRule: ZoneAvoidanceRule

IPing ribbonPing: NoOpPing

ServerList ribbonServerList: ConfigurationBasedServerList

ServerListFilter ribbonServerListFilter: ZonePreferenceServerListFilter

ILoadBalancer ribbonLoadBalancer: ZoneAwareLoadBalancer

二、建一个服务消费者

重新新建一个spring-boot工程,取名为:service-ribbon;

在它的pom.xml文件分别引入起步依赖spring-cloud-starter-eureka、spring-cloud-starter-ribbon、spring-boot-starter-web,代码如下:
 

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.forezp</groupId>
<artifactId>service-ribbon</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service-ribbon</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
 


在工程的配置文件指定服务的注册中心地址为http:/ /localhost:8761/eureka/,程序名称为 service-ribbon,程序端口为8764。配置文件application.yml如下:
 

eureka:
client:
serviceUrl:
defaultZone: https://localhost:8761/eureka/
server:
port: 8764
spring:
application:
name: service-ribbon


 
在工程的启动类中,通过@EnableDiscoveryClient向服务中心注册;并且向程序的ioc注入一个bean: restTemplate;并通过@LoadBalanced注解表明这个restRemplate开启负载均衡的功能。
 

@SpringBootApplication
@EnableDiscoveryClient
public class ServiceRibbonApplication {

public static void main(String[] args) {
SpringApplication.run(ServiceRibbonApplication.class, args);
}

@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}

}
 


写一个测试类HelloService,通过之前注入ioc容器的restTemplate来消费service-hi服务的“/hi”接口,在这里我们直接用的程序名替代了具体的url地址,在ribbon中它会根据服务名来选择具体的服务实例,根据服务实例在请求的时候会用具体的url替换掉服务名,代码如下:

 
@Service
public class HelloService {

@Autowired
RestTemplate restTemplate;

public String hiService(String name) {
return restTemplate.getForObject("https://SERVICE-HI/hi?name="+name,String.class);
}

}


 
写一个controller,在controller中用调用HelloService 的方法,代码如下:
 

/**
* Created by fangzhipeng on 2017/4/6.
*/
@RestController
public class HelloControler {

@Autowired
HelloService helloService;
@RequestMapping(value = "/hi")
public String hi(@RequestParam String name){
return helloService.hiService(name);
}


}
 


在浏览器上多次访问http:/ /localhost:8764/hi?name=forezp,浏览器交替显示:
 

hi forezp,i am from port:8762

hi forezp,i am from port:8763


 
这说明当我们通过调用restTemplate.getForObject(“http:/ /SERVICE-HI/hi?name=“+name,String.class)方法时,已经做了负载均衡,访问了不同的端口的服务实例。 java B2B2C springmvc mybatis仿淘宝电子商城系统


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